Apple Store gift cards received by email.
Have tried multiple sources to no avail: How can I purchase something online from apple.com using an Apple Store (NOT app store) gift card sent to me via email (i.e. does not have a "back" containing a phone # to call).
I have spent much greater value of my time & patience trying to redeem these, where no one has a definitive answer, such that loyalty to Apple is wearing thin from their interlocking repetitive names (apple pay, apple card, apple store, app store, app gift card, apple store gift card, apple wallet; it's like an elementary school work sheet--which of these things belong together and which are different?).